/*
 * Copyright (c) 2013, SRI International
 * All rights reserved.
 * Licensed under the The BSD 3-Clause License;
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 * 
 * http://opensource.org/licenses/BSD-3-Clause
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the aic-web-praise nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.sri.ai.lpitools.executionengine.server.components.queryListener;

import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;

import java.util.logging.Logger;

import com.google.gson.Gson;
import com.sri.ai.lpitools.executionengine.server.callback.CallBackClient_Interface;

/**
 * This class queues up nodes to be sent as a bundle.
 * @author dabraham
 *
 */
public class TreeNodeQueue {
	private ArrayList<Vector<String>> list = new ArrayList<Vector<String>>();
	private CallBackClient_Interface client;
	private boolean isScheduled = false;
	private Timer timer = new Timer();
	private final int SEND_DELAY = 250;
	private static final Logger logger = Logger.getLogger(TreeNodeQueue.class.getName());
	/**
	 * Sets the XMLRPC Client with which nodes will be sent.
	 * @param client
	 */
	public void setClient(CallBackClient_Interface client) {
		this.client = client;
	}
	
	/**
	 * Adds a node to the list of nodes to be sent.
	 * @param treeNode the node to be sent, a GSON-serialized TreeNode.
	 * @param panelID the ID of the panel to which the node belongs.
	 */
	public void EnqueueNode(String treeNode, String clientID)
	{
		synchronized(list)
		{
			//If a send is not currently scheduled, schedule one.
			if(!isScheduled)
			{
				timer.schedule(
						new TimerTask(){

							@Override
							public void run() {
								sendList();								
							}
						}
						, SEND_DELAY);
				isScheduled = true;
			}
			//create the node package and add it to the list.
			Vector<String> toAdd = new Vector<String>();
			toAdd.add(treeNode);
			toAdd.add(clientID);
			list.add(toAdd);
		}
	}
	
	/**
	 * Checks whether a send is currently scheduled.
	 * @return the value of isScheduled.
	 */
	public boolean isSendScheduled()
	{
		return isScheduled;
	}

	/**
	 * Serializes the list and sends it to the webclient,
	 * Then clears the list and marks that the send has been completed.
	 */
	private void sendList() {
		synchronized(list)
		{
			List<String> mainList = new ArrayList<String>();
			String mainClientID = null;
			
			List<Vector<String>> otherList = new ArrayList<Vector<String>>();
			for(Vector<String> current: list){
				String node = current.get(0);
				String clientID = current.get(1);
				if(mainClientID == null){
					mainClientID = clientID;
					mainList.add(node);
				}
				else if(mainClientID.equalsIgnoreCase(clientID)) {
					mainList.add(node);
				}
				else if(!mainClientID.equalsIgnoreCase(clientID)) {
					logger.info("Found a node in the queue that did not match the main list " + clientID);
					otherList.add(current);
				}
				
			}
			
			String toSend = new Gson().toJson(mainList);
			client.addBundledTreeNodes(toSend, mainClientID);
			
			if(otherList.size() > 0){
				for(Vector<String> current: otherList){
					List<String> newList = new ArrayList<String>();
					String node = current.get(0);
					String clientID = current.get(1);
					newList.add(node);
					String toSendOther = new Gson().toJson(newList);
					client.addBundledTreeNodes(toSendOther, clientID);

				}
			}
			list.clear();
			isScheduled = false;
		}
	}
	
}
